InterruptWait(), InterruptWait_r()

QNX SDP8.0C Library ReferenceAPIDeveloper

Wait for a hardware interrupt

Synopsis:

#include <sys/neutrino.h>

int InterruptWait( int flags,
                   const uint64_t * timeout );

int InterruptWait_r( int flags,
                     const uint64_t * timeout );

Arguments:

flags

A bitwise OR of zero or more of the following values:

_NTO_INTR_WAIT_FLAGS_FAST
_NTO_INTR_WAIT_FLAGS_UNMASK

For more information, see Flags, below.

timeout

This should currently be NULL. This may change in future versions.

Note: Use TimerTimeout() to achieve a timeout.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The InterruptWait() or InterruptWait_r() kernel calls wait for a hardware interrupt. These calls block while waiting for an interrupt to occur. For more information, see Blocking states below.

The InterruptWait() and InterruptWait_r() functions are identical except in the way they indicate errors. See the Returns section for details.

On a multicore system, a thread that calls InterruptWait() runs on any CPU, limited only by the scheduler and the runmask.

Flags

The flags argument is a bitwise OR of zero or more of the following values:

_NTO_INTR_WAIT_FLAGS_FAST: Use a lightweight blocking mechanism when waiting for an interrupt. Timeouts aren't supported if you use this flag.
Note: This flag is only valid from an IST that called InterruptAttachThread().
_NTO_INTR_WAIT_FLAGS_UNMASK: Unmask the interrupt before waiting. You won't need to call InterruptUnmask().

Blocking states

STATE_INTR: If the calling thread called InterruptAttachThread() and became an IST, the kernel blocks the IST on its interrupt semaphore while waiting for an interrupt to occur.; If the calling thread called InterruptAttachEvent() or InterruptAttachEventPriority() to create an IST, the thread blocks waiting for the IST to notify it with a type SIGEV_INTR event (i.e., a hardware interrupt) when an interrupt occurs.

Returns:

The only difference between these functions is the way they indicate errors:

InterruptWait(): If an error occurs, -1 is returned and errno is set. Any other value returned indicates success.
InterruptWait_r(): EOK is returned on success. This function does NOT set errno. If an error occurs, any value in the Errors section may be returned.

Errors:

EINTR: The call was interrupted by a signal.
ENOTSUP: The reserved arguments aren't NULL.
ETIMEDOUT: A kernel timeout unblocked the call. See TimerTimeout().

Classification:

QNX OS


Safety:
Cancellation point	No
Signal handler	Yes
Thread	Yes

Page updated: May 17, 2024